MathDB
Find the area of triangle OEF

Source: Iran Third Round Problems 1993 – Poblem 2

July 29, 2011
geometrygeometry proposed

Problem Statement

In the figure below, area of triangles AOD,DOC,AOD, DOC, and AOBAOB is given. Find the area of triangle OEFOEF in terms of area of these three triangles.
[asy] import graph; size(11.52cm); real lsf=0.5; pen dps=linewidth(0.7)+fontsize(10); defaultpen(dps); pen ds=black; real xmin=-2.4,xmax=9.12,ymin=-6.6,ymax=5.16; pair A=(0,0), F=(9,0), B=(4,0), C=(3.5,2), D=(1.94,2.59), O=(2.75,1.57); draw(A--(3,4),linewidth(1.2)); draw((3,4)--F,linewidth(1.2)); draw(A--F,linewidth(1.2)); draw((3,4)--B,linewidth(1.2)); draw(A--C,linewidth(1.2)); draw(B--D,linewidth(1.2)); draw((3,4)--O,linewidth(1.2)); draw(C--F,linewidth(1.2)); draw(F--O,linewidth(1.2)); dot(A,ds); label("AA",(-0.28,-0.23),NE*lsf); dot(F,ds); label("FF",(8.79,-0.4),NE*lsf); dot((3,4),ds); label("EE",(3.05,4.08),NE*lsf); dot(B,ds); label("BB",(4.05,0.09),NE*lsf); dot(C,ds); label("CC",(3.55,2.08),NE*lsf); dot(D,ds); label("DD",(1.76,2.71),NE*lsf); dot(O,ds); label("OO",(2.57,1.17),NE*lsf); clip((xmin,ymin)--(xmin,ymax)--(xmax,ymax)--(xmax,ymin)--cycle); [/asy]